The present exemplary embodiment relates to liquid dispensers. It finds particular application in conjunction with small volume, analytical liquid dispensers, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications.
Three types of bio-ejection systems dominate the market today.
The first type consists of a large reservoir of liquid, connected to an ejection system via tubing. For example, in certain systems, one or more tubes are in communication with a very fine tube. Pressure pulses behind the liquid cause droplet ejection off the end of the small flow volume tube. In this system, the reservoir filling volume may not be critical, and once the tubing is charged or primed, there is little need for anything other than consistent ejection.
A second type of system is based upon contact printing. In this arrangement, an array of needles is dipped into a supply of liquid. A droplet of liquid wets each needle or pin as the array is withdrawn from the supply. The residual drop is then contacted to the substrate where the drop wicks onto the surface.
A third system aspirates and ejects. In this type of system, the liquid is drawn into the ejection system from a liquid supply. Once in the ejection mechanism, all or portions of the drawn volume may be ejected.
All of these systems are fixed systems and hardware intensive. Furthermore, the systems are relatively expensive.
Traditionally, filling single ejectors has been performed manually. In order to simplify the filling, it would be convenient to fill an ejector without monitoring quantity, time, or other parameters. If the filling stopped when the internal reservoirs filled to their maximum, without any close monitoring, that would render the filling system much easier to build and manage. Accordingly, a need exists for such a filling configuration.